Reduction of power consumption is a prime consideration in the design of communication equipment, and particularly in battery-operated wireless communication terminals. Some wireless terminals reduce power consumption by intermittently shutting down Radio Frequency (RF) circuitry. For example, U.S. Pat. No. 7,881,252 and U.S. Patent Application Publication 2010/0284379, whose disclosures are incorporated herein by reference, describe a wireless receiver with intermittent shut-off of RF circuits. The terminal includes an RF receiver, which is configured to receive and down-convert an RF signal. The RF signal includes a sequence of downlink frames, each downlink frame including at least a map zone followed by a data zone.
The map zone contains an indication of a time allocation in the data zone during which downlink data will be transmitted to the terminal. An analog/digital (A/D) converter converts the output signal from the RF receiver into a stream of digital samples. A digital processing circuit processes the digital samples so as to identify the time allocation and to recover the downlink data transmitted during the identified time allocation, while shutting down the RF receiver during at least one interval during the downlink frame that is outside the identified time allocation.